html {
    height: 100%;
    width: 100%;
    overflow: hidden;
}

body {
    margin: 0px;
    padding: 0px;
    width: 100%;
    height: 100%;
}

#screen {
    border: 1px solid black;
    position: absolute;
}

#btnTest {
    top : 650px;
    position: absolute;
}

